export default {
  bind(el, binding, vnode, oldVnode) {
    // 初始非全屏
    let isFullScreen = false
    // 当前宽高
    let nowWidth = 0
    let nowHight = 0
    // 获取屏幕宽度
    const swidth = document.body.clientWidth
    // 当前顶部高度
    let nowMarginTop = 0
    // 获取弹框头部（这部分可双击全屏） 12-17 bug 放大有问题
    const dialogHeaderEl = el.querySelector('.el-dialog__header')
    let hasSetBodyHight = false
    // 弹窗
    const dragDom = el.querySelector('.el-dialog')
    // 给弹窗加上overflow auto；不然缩小时框内的标签可能超出dialog；
    // dragDom.style.overflow = "auto";
    // 清除选择头部文字效果
    dialogHeaderEl.onselectstart = new Function('return false')
    // 头部加上可拖动cursor
    dialogHeaderEl.style.cursor = 'move'

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const sty = dragDom.currentStyle || window.getComputedStyle(dragDom, null)

    // 头部插入最大化最小化元素
    const maxMin = document.createElement('button')
    maxMin.className += ' el-dialog__headerbtn el-dialog__minmax'
    maxMin.style.right = '40px'
    maxMin.style.color = '#909399'
    maxMin.title = '最大化'
    // maxMin.innerHTML = '<i class="el-icon-full-screen" onMouseOver="this.style.color=\'#409EFF\'" onMouseOut="this.style.color=\'inherit\'"></i>';
    dialogHeaderEl.insertBefore(maxMin, dialogHeaderEl.childNodes[1])

    // 获取原有属性 ie dom元素.currentStyle 火狐谷歌 window.getComputedStyle(dom元素, null);
    const getStyle = (function() {
      if (window.document.currentStyle) {
        return (dom, attr) => dom.currentStyle[attr]
      } else {
        return (dom, attr) => getComputedStyle(dom, false)[attr]
      }
    })()
    dialogHeaderEl.onmousedown = (e) => {
      // 鼠标按下，计算当前元素距离可视区的距离
      const disX = e.clientX - dialogHeaderEl.offsetLeft
      const disY = e.clientY - dialogHeaderEl.offsetTop

      const dragDomWidth = dragDom.offsetWidth
      const dragDomHeight = dragDom.offsetHeight

      const screenWidth = document.body.clientWidth
      const screenHeight = document.body.clientHeight

      const minDragDomLeft = dragDom.offsetLeft
      const maxDragDomLeft = screenWidth - dragDom.offsetLeft - dragDomWidth

      const minDragDomTop = dragDom.offsetTop
      const maxDragDomTop = screenHeight - dragDom.offsetTop - dragDomHeight

      // 获取到的值带px 正则匹配替换
      let styL = getStyle(dragDom, 'left')
      let styT = getStyle(dragDom, 'top')

      if (styL.includes('%')) {
        styL = +document.body.clientWidth * (+styL.replace(/\%/g, '') / 100)
        styT = +document.body.clientHeight * (+styT.replace(/\%/g, '') / 100)
      } else {
        styL = +styL.replace(/\px/g, '')
        styT = +styT.replace(/\px/g, '')
      }

      document.onmousemove = function(e) {
        // 通过事件委托，计算移动的距离
        let left = e.clientX - disX
        let top = e.clientY - disY

        // 边界处理
        if (-(left) > minDragDomLeft) {
          left = -minDragDomLeft
        } else if (left > maxDragDomLeft) {
          left = maxDragDomLeft
        }

        if (-(top) > minDragDomTop) {
          top = -minDragDomTop
        } else if (top > maxDragDomTop) {
          top = maxDragDomTop
        }

        // 移动当前元素
        dragDom.style.cssText += `;left:${left + styL}px;top:${top + styT}px;`

        // emit onDrag event
        vnode.child.$emit('dragDialog')
      }

      document.onmouseup = function(e) {
        document.onmousemove = null
        document.onmouseup = null
      }
    }
    // dialogHeaderEl.onmousedown = moveDown;
    let bodyHeight = 'auto'
    function setMaxMin() {
      if (isFullScreen == false) {
        const i = maxMin.querySelector('.el-icon-full-screen')
        i.classList.remove('el-icon-full-screen')
        i.classList.add('el-icon-crop')
        maxMin.title = '还原'
        bodyHeight = dragDom.querySelector('.el-dialog__body').offsetHeight + 'px'
        nowHight = dragDom.clientHeight
        nowWidth = dragDom.clientWidth
        nowMarginTop = dragDom.style.marginTop
        dragDom.style.left = 0
        dragDom.style.top = 0
        dragDom.style.height = '100VH'
        dragDom.style.width = '100VW'
        dragDom.style.marginTop = 0
        isFullScreen = true
        dialogHeaderEl.style.cursor = 'initial'
        dialogHeaderEl.onmousedown = null
        if (!hasSetBodyHight) {
          dragDom.querySelector('.el-dialog__body').style.height = 'calc(100% - ' + dialogHeaderEl.offsetHeight + 'px)'
          hasSetBodyHight = true
        }
      } else {
        const i = maxMin.querySelector('.el-icon-crop')
        i.classList.remove('el-icon-crop')
        i.classList.add('el-icon-full-screen')
        // maxMin.innerHTML = '<i class="el-icon-full-screen"></i>';
        maxMin.title = '最大化'
        dragDom.style.height = 'auto'
        dragDom.style.width = nowWidth + 'px'
        dragDom.style.marginTop = nowMarginTop
        isFullScreen = false
        dialogHeaderEl.style.cursor = 'move'
        // dialogHeaderEl.onmousedown = moveDown;
        dragDom.querySelector('.el-dialog__body').style.height = bodyHeight
        hasSetBodyHight = false
      }
    }
    // 点击放大缩小效果
    // maxMin.onclick = setMaxMin;
    // 双击头部效果
    // dialogHeaderEl.ondblclick = setMaxMin;
  }
}

